ISRO’s PSLV-C58 XPoSat: A Revolutionary Contribution to Space Research

While India has already established space-based X-ray astronomy with a focus on imaging and time domain studies, XPoSat’s mission goes beyond by measuring the polarisation of X-rays in the energy band of 8-30 keV emitted by approximately 50 potential cosmic sources.

ISRO, the Indian Space Research Organisation, kicked off 2024 with a remarkable accomplishment. On January 1, ISRO achieved a successful launch of India’s inaugural X-Ray Polarimeter Satellite, known as XPoSat, aboard the Polar Satellite Launch Vehicle rocket, PSLV-C58, from the Satish Dhawan Space Centre in Sriharikota. In its 60th mission, the PSLV-C58 rocket flawlessly deployed the XPoSat payload into Low Earth Orbit.

XPoSat is specifically designed to conduct research on space-based polarisation measurements of X-ray emissions from celestial sources. The primary payload of XPoSat is POLIX (Polarimeter Instrument in X-Rays), developed by the Raman Research Institute, which aims to measure polarimetry parameters. Additionally, the XSPECT (X-ray Spectroscopy and Timing) payload, constructed by the U R Rao Satellite Centre in Bengaluru, will provide valuable spectroscopic information.

This mission signifies a significant enhancement for the scientific community. While India has already established space-based X-ray astronomy with a focus on imaging and time domain studies, XPoSat’s mission goes beyond by measuring the polarisation of X-rays in the energy band of 8-30 keV emitted by approximately 50 potential cosmic sources. This will enable extensive spectral and temporal studies of cosmic X-ray sources in the long run.

A Stellar Display of Prowess

Following the triumph of ISRO’s Gaganyaan Test Vehicle D1 mission in October, the launch of XPoSat took place. In 2023, India reached new heights with the successful gentle landing of Chandrayaan-3 on the Moon’s south pole and the commencement of Aditya-L1, India’s inaugural solar mission.

The primary objective of Chandrayaan-3, India’s first triumphant lunar landing mission, was to showcase a gentle landing near the lunar south polar region and conduct experiments utilizing the instruments aboard the lander ‘Vikram’ and rover ‘Pragyaan’. On August 23, the Vikram Lander achieved its historic touchdown on the Moon, and subsequently, the Pragyan rover was deployed to explore the uncharted lunar south pole.

India’s future aspirations include the Gaganyaan Mission, the establishment of the ‘Bharatiya Antariksha Station’ by 2035, and sending the first Indian to the Moon by 2040.

In addition to ISRO, the U.S.-based National Aeronautics Space Agency (NASA) conducted a similar investigation known as the Imaging X-Ray Polarimetry Explorer mission in December 2021. This mission focused on studying the remnants of supernova explosions, the particle streams emitted by black holes, and other cosmic events. X-ray polarisation serves as a vital diagnostic tool for examining the radiation mechanism and geometry of celestial sources. With the launch of XPoSat, ISRO has made a significant contribution to the global scientific community.